Field of the Invention
The invention relates to a high-temperature-resistant component made from a nickel-base superalloy. The invention also relates to a process for producing the component.
German Published, Non-Prosecuted Patent Application DE 23 33 775 B2 describes a process for the heat treatment of a nickel alloy. The nickel alloy includes up to 0.3% of carbon, 11–15% of chromium, 8–12% of cobalt, 1–2.5% of molybdenum, 3–10% of tungsten, 3.5–10% of tantalum, 3.5–4.5% of titanium, 3–4% of aluminum, 0.005–0.025% of boron, 0.05–0.4% of zirconium and a remainder of nickel. Furthermore, the alloy additionally includes 0.01–3% of hafnium, so that a block-like carbide formation and a finely dispersed precipitation of an Ni3(Al,Ti) phase is achieved through a suitable heat treatment. There is no mention of rhenium or ruthenium being added.
U.S. Pat. No. 5,611,670 discloses a rotor blade for a gas turbine. The rotor blade has a monocrystalline platform area and a monocrystalline blade part. A securing area of the blade is constructed with a directionally solidified structure. The blade is cast from a superalloy which has the following composition, in percent by weight: up to 0.2% of carbon, 5–14% of chromium, 4–7% of aluminum, 2–15% of tungsten, 0.5–5% of titanium, up to 3% of niobium, up to 6% of molybdenum, up to 12% of tantalum, up to 10.5% of cobalt, up to 2% of hafnium, up to 4% of rhenium, up to 0.035% of boron, up to 0.035% of zirconium and a remainder of nickel. Those wide ranges are used to specify alloy compositions which are suitable, in principle, for proposed gas turbine blades, but do not indicate a composition range which is appropriate with a view to a particular resistance to oxidation and corrosion or strength.
European Patent EP 0 297 785 B1 has disclosed a nickel-base superalloy for single crystals. The superalloy has the following composition, in percent by weight: 6–15% of chromium, 5–12% of tungsten, 0.01–4% of rhenium, 3–9% of tantalum, 0.5–2% of titanium, 4–7% of aluminum and optionally 0.5–3% of molybdenum. This superalloy results both in a resistance to high-temperature cracking and in a resistance to corrosion. The titanium content must not exceed 2% by weight in order not to impair the resistance to corrosion.
U.S. Pat. No. 5,122,206 has disclosed a nickel-base superalloy which has a particularly narrow coexistence zone for the solid and liquid phases and is therefore particularly suitable for a single-crystal casting process. The alloy has the following composition, in percent by weight: 10–30% of chromium, 0.1–5% of niobium, 0.1–8% of titanium, 0.1–8% of aluminum, 0.05–0.5% of copper or, instead of copper, 0.1–3% of tantalum. In the former case, hafnium or rhenium may optionally also be present, in an amount of from 0.05–3%, while in the latter case 0.05–0.5% of copper may also be present instead of rhenium or hafnium. Furthermore, it is optionally possible to provide 0.05–3% of molybdenum or tungsten.